In the regulation of fuel/air ratios for internal combustion engines, a regulation may be superimposed on precontrol. Further correction quantities may be derived from the behavior of the regulated quantity, in order to compensate for mismatches of the precontrol to changed operating conditions. This compensation is also called adaptation. U.S. Pat. No. 4,584,982, for example, discusses an adaptation having different adaptation quantities in different ranges of the load/speed spectrum of an internal combustion engine. The various adaptation quantities are directed towards the compensation of different errors. With respect to cause and effect, three types of error may be distinguished: Errors of a hot film air mass meter have a multiplicative effect on fuel metering. Unmetered air influences have an additive effect per time unit, and errors in the compensation of the response delay of the fuel injectors have an additive effect per injection.
It has been shown that, even at complete adaptation in the hot state, mismatches at low engine temperatures continue to appear, which disappear again at higher temperatures.